Hydrokinetic torque converter

ABSTRACT

A hydrokinetic torque converter for use with a transmission in the power train of a motor vehicle has a housing rotatable by the engine and containing a pump, a turbine and at least one stator as well as a rotary output device connected to the input shaft of the transmission. The pump is normally rotatable by the housing; the turbine is rotatable (a) by the fluid which is circulated by the pump or (b) by the housing in response to engagement of a lockup clutch; and the stator can be connected to the stationary case of the transmission or is rotatable by the circulating fluid. First and second hubs are non-rotatably but axially movably mounted on the output member and are respectively connectable with the turbine and the stator by suitable clutches. The hubs can move axially relative to the output device between several positions in one of which the turbine can drive the input element of the transmission in a forward direction, in another of which the stator can rotate the input element in a direction to drive the vehicle rearwardly, and in a third of which the transmission is in neutral gear.

This is a division of application Ser. No. 09/089,570, filed Jun. 3,1998 now U.S. Pat. No. 6,050,375. Each of these prior applications ishereby incorporated herein by reference, in its entirety.

BACKGROUND OF THE INVENTION

The invention relates to improvements in hydrokinetic or hydrodynamictorque converters.

A standard hydrokinetic torque converter comprises certain basiccomponents including a housing, a pump which is confined in the housingand receives torque from a suitable prime mover (such as by way of thehousing), a turbine in the housing, and an optional stator in thehousing. The turbine receives torque from the pump and drives an outputelement, e.g., the input shaft of a transmission if the torque converteris installed in the power train of a motor vehicle between an internalcombustion engine (which drives the housing) and a variable speedtransmission, particularly an automated transmission. The ratio of thetransmission is or can be changed by one or more suitable actuators toshift the transmission into neutral, reverse or a selected forward gear.When utilized in conjunction with an automated transmission, a torqueconverter can serve as a means for starting, as a means for equalizingthe RPM of the input element of the transmission with the engine RPMand, if necessary, also as a torque increasing or amplifying means.

Presently known automated transmissions in the power trains of motorvehicles are designed in such a way that a shifting from a forward gearinto reverse gear, or vice versa, necessitates the shifting into anintermediate gear. For example, an automated transmission of suchcharacter can embody a suitable planetary gearing. A drawback of suchtransmissions is that they are complex and expensive because each suchtransmission comprises a large number of in part complex componentswhich contributes to the initial, assembly and maintenance cost of thetransmission and of the entire power train.

OBJECTS OF THE INVENTION

An object of the invention is to provide a hydrokinetric torqueconverter which renders it possible to employ a relatively simple,compact and inexpensive transmission, particularly an automatedtransmission, when such apparatus are utilized in the power train of amotor vehicle.

Another object of the invention is to provide a hydrokinetic torqueconverter which renders it possible to change ratio of an automatedtransmission from forward to reverse or vice versa in a novel andimproved way.

A further object of the invention is to provide a hydrokinetic torqueconverter which renders it possible to reduce the fuel consumption ofthe internal combustion engine in the power train of a motor vehicle inwhich the torque converter and a transmission are being put to use.

An additional object of the invention is to provide a novel and improvedpower train which embodies the above outlined hydrokinetic torqueconverter and can be utilized in a motor vehicle to transmit torque fromthe engine to the wheels of the vehicle.

Still another object of the invention is to provide a hydrokinetic orhydrodynamic torque converter wherein the turbine(s), the pump(s), thestator(s) and/or the associated parts in the rotary housing of thetorque converter are distributed and cooperate in a novel and improvedway.

A further object of the invention is to provide a novel and improvedsystem or combination of torque transmitting components (such as clawclutches and/or other types of clutches) which can be utilized in orwith a hydrokinetic torque converter of the above outlined character.

Another object of the invention is to provide a novel and improvedarrangement of actuators for the aforementioned torque transmittingcomponents to influence the direction of rotation and/or otherparameters of the rotary output element of the torque converter, such asthe input shaft of an automated transmission in the power train of amotor vehicle.

An additional object of the invention is to provide a novel and improvedarrangement of synchronizers for use in the housing of or with the aboveoutlined hydrokinetic torque converter to influence the accelerationand/or deceleration of various rotary constituents which serve totransmit torque to the rotary output element of the torque converter.

Still another object of the invention is to provide a novel and improvedapparatus for selecting the magnitude and/or other parameters of torquebeing transmitted or being transmissible to a transmission (such as anautomated transmission) in the power train of a motor vehicle.

A further object of the invention is to provide a novel and improvedlockup clutch or bypass clutch for use in the above outlinedhydrokinetic torque converter.

Another object of the invention is to provide a hydrokinetic torqueconverter which can be utilized as a superior substitute forconventional torque converters in the power trains of existing types ofmotor vehicles.

SUMMARY OF THE INVENTION

One feature of the invention resides in the provision of a hydrokinetictorque converter which comprises a rotary housing, a pump which isconfined in and is rotatable by the housing, a rotary turbine componentand at least one rotary stator component in the housing, a drive (suchas an internal combustion engine of a motor vehicle) for the housing, anoutput device rotatable in the housing in a clockwise and in acounter-clockwise direction, means for connecting the output device withone of the components to rotate the output device in one of the twodirections, and means for connecting the output device with the other ofthe components to rotate the output device in the other direction.

At least one of the connecting means can comprise at least oneengageable and disengageable clutch which permits the respectivecomponent to rotate relative to the output device in the disengagedcondition of the clutch.

The torque converter can be utilized with advantage with a transmissionhaving a stationary case and a rotary input element (such as a shaft)which is arranged to receive torque from the output device. At least oneof the connecting means can include a hub which non-rotatably andaxially movably surrounds the output device, and at least one engageableand disengageable clutch which is arranged to transmit torque betweenthe respective component and the hub in the engaged condition of theclutch. Such torque converter preferably further comprises an engageableand disengageable form-locking connection between the hub and the caseof the transmission. The form-locking connection can comprise a firstgear which is provided on the transmission case and a second gear whichis provided on the hub and is arranged to mate with the first gear inthe engaged condition of the form-locking connection.

At least one of the two connecting means can comprise at least oneform-locking clutch, e.g., a claw clutch. Alternatively, the at leastone connecting means can comprise at least one friction clutch.

Another feature of the invention resides in the provision of ahydrokinetic torque converter which comprises a rotary housing, a pumpwhich is confined in and is rotatable by the housing, a drive (such asthe aforementioned engine) for the housing, a rotary turbine and atleast one stator provided in the housing, a rotary output device (suchas a shaft) which is rotatable in clockwise and counterclockwisedirections, means for connecting the output device with the turbine torotate the output device in one of the clockwise and counterclockwisedirections, and means for connecting the output device with the at leastone stator to rotate the output device in the other direction. Thetorque converter has a first operating mode in which the output deviceis connected with the turbine to rotate in the one direction, and asecond operating mode in which the output device is connected with theat least one stator to rotate in the other direction.

The torque converter can be set to assume a third operating mode inwhich the output device is disconnected from the turbine as well as fromthe at least one stator.

Such torque converter can further comprise at least one engageable anddisengageable clutch which is arranged to transmit torque between theturbine and the output device in the first operating mode of the torqueconverter. This torque converter can further comprise a rotary hub whichis arranged to receive torque from the at least one clutch, and aform-locking connection which serves to transmit torque between the huband the output device.

Still further, the torque converter can comprise at least one engageableand disengageable clutch which is arranged to transmit torque betweenthe at least one stator and the output device in the second operatingcondition or mode of the torque converter. This torque converter canfurther comprise a rotary hub serving to receive torque from the atleast one clutch, and a form-locking connection which serves to transmittorque between the hub and the output device.

At least one of the connecting means can comprise gears which aremovable into and out of mesh with each other.

The means for connecting the turbine with the output device can comprisea hub which non-rotatably but axially movably surrounds the outputdevice, and at least one engageable and disengageable clutch whichserves to connect the turbine with the hub and to disconnect the turbinefrom the hub. If such torque converter is used in connection with atransmission (such as an automated transmission) having a stationarycase and a rotary input element arranged to receive torque from theoutput device, the torque converter preferably further comprises aseparable form-locking connection between the turbine and thetransmission case.

The means for connecting the at least one stator with the output devicecan comprise a hub which non-rotatably but axially movably surrounds theoutput device, and at least one engageable and disengageable clutchwhich is arranged to connect the at least one stator with and todisconnect the at least one stator from the hub. If such torqueconverter is utilized in conjunction with a variable-speed transmissionhaving a stationary case and a rotary input element adapted to receivetorque from the output device of the torque converter, the latterpreferably further comprises a separable form-locking connection betweenthe at least one stator and the transmission case.

A further feature of the invention resides in the provision of ahydrokinetic torque converter which comprises a housing rotatable abouta predetermined axis, means (such as the camshaft or the crankshaft ofan internal combustion engine in the power train of a motor vehicle) forrotating the housing, a pump in the housing, a turbine which isrotatable in the housing, at least one stator which is rotatable in thehousing, a rotary output device in the housing, first and second hubsnon-rotatably but axially movably surrounding the output device, meansfor separably connecting the turbine with the first hub to rotate theoutput device in a first direction, means for separably connecting theat least one stator with the second hub to rotate the output device in asecond direction counter to the first direction, and means for movingthe hubs axially of the output device between a plurality of positionsincluding a first position in which the first hub can receive torquefrom the turbine and a second position in which the second hub canreceive torque from the at least one stator.

Such torque converter can further comprise means (such as a thrustbearing) for rotatably coupling the hubs to each other for jointmovement in the axial direction of the output device.

The means for moving the hubs axially of the output device can compriseat least one fluid-operated motor including a reciprocable piston; suchpiston preferably includes at least one of the two hubs.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved torque converter itself, however, both as to its constructionand its mode of operation, together with numerous additional importantand advantageous features and attributes thereof, will be bestunderstood upon perusal of the following detailed description of certainpresently preferred specific embodiments with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary schematic axial sectional view of a hydrokinetictorque converter which embodies one form of the invention and isinstalled between the engine and the transmission in the power train ofa motor vehicle;

FIG. 2 is a fragmentary schematic axial sectional view of a secondhydrokinetic torque converter with the turbine connected to the outputdevice;

FIG. 3 illustrates the structure of FIG. 2 but with the stator connectedto the output device;

FIG. 4 is a fragmentary axial sectional view of a third torqueconverter;

FIG. 4a is an enlarged view of a detail in the torque converter of FIG.4;

FIG. 5 is a fragmentary axial sectional view of a fourth torqueconverter;

FIG. 6 is a similar fragmentary axial sectional view of a fifth torqueconverter constituting a modification of the torque converter which isshown in FIG. 5;

FIG. 7 illustrates certain details of the structure which is shown inFIG. 4a but in different axial positions of the hubs;

FIG. 8 is a schematic fragmentary axial sectional view of still anotherhydrokinetic torque converter and of a portion of a transmission whichreceives torque from the output device of the torque converter;

FIG. 9 is a fragmentary schematic axial sectional view of a furtherhydrokinetic torque converter;

FIG. 10 is a similar fragmentary schematic axial sectional view of atorque converter constituting a modification of the torque converterwhich is shown in FIG. 9;

FIG. 11a is a fragmentary schematic axial sectional view of a furthertorque converter with the hubs for the turbine and the statorsillustrated in first axial positions in which the output device of thetorque converter set to to transmit torque in a direction to cause thetransmission to drive the motor vehicle in reverse;

FIG. 11b illustrates the structure of FIG. 11a but with the hubs inaxial positions in which the transmission is ready to drive the motorvehicle in a forward direction;

FIG. 11c illustrates the structure of FIGS. 11a and 11 b but with thehubs in axial positions in which the transmission is in neutral gear;

FIG. 12 is a fragmentary schematic axial sectional view of ahydrokinetic torque converter constituting a modification of the torqueconverter which is illustrated in FIGS. 11a to 11 c; and

FIG. 13 is a fragmentary schematic axial sectional view of still anotherhydrokinetic torque converter constituting a modification of the torqueconverters shown in FIGS. 11a- 11 c and FIG. 12.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring first to FIG. 1, there is shown one-half of a hydrokinetic orhydrodynamic (hereinafter called hydrokinetic) torque converter 1 whichembodies one form of the present invention. The housing 2 of the torqueconverter 1 is rotatable about an axis I—I and contains a pump 3, aturbine 8 and a stator 11. A substantially radial wall 2 a of thehousing 2 is adjacent and is connected to the rotary output member of asuitable prime mover, e.g., to the crankshaft or the camshaft of aninternal combustion engine in the power train of a motor vehicle.

The pump 3 is rotated by and its vanes or blades (not specifically shownin FIG. 1) can be affixed to or of one piece with the housing 2. Aconnector 4 is provided to operatively connect the pump 3 with a bearing5 and a sealing element 6 which are provided to rotatably and sealinglycouple the pump 3 with the case 7 of a transmission.

The turbine 8 is installed in the housing 2 between the pump 3 and theaforementioned substantially radial wall 2 a. The stator 11 is disposedbetween the pump 3 and the turbine 8. A connector 10 is employed tocouple the turbine 8 with a hub 12 in response to engagement of anengageable and disengageable clutch 13. The latter is shown in FIG. 1 inthe engaged condition, i.e., the turbine 8 can transmit torque to thehub 12.

A further connector 9 is provided to establish a form-locking connectionbetween the turbine 8 and a hub 15 for the stator 11 in response toengagement of a second engageable and disengageable clutch 14. FIG. 1shows the clutch 14 in the disengaged condition, i.e., the turbine 8 canrotate relative to the stator 11.

An additional connector 17 serves to connect the stator 11 with the hub12 in response to the engagement of a third engageable and disengageableclutch 18 (shown in FIG. 1 in the disengaged condition), and stillanother connector 16 serves to couple the stator 11 with the hub 15 inresponse to engagement of an engageable and disengageable clutch 19(shown in FIG. 1 in the disengaged condition).

The aforementioned clutch 14 can establish a connection between theconnector 9 and the hub 15 or between the hub 15 and a gear 20 which isrigid with the non-rotatable transmission case 7.

The reference character 22 denotes a rotary output element of the torqueconverter 1, and such output element 22 can constitute the rotary inputelement (such as a shaft) of the transmission in the case 7. FIG. 1shows the clutch 13 in that (engaged) condition in which the turbine 8can transmit torque to the hub 12 which, in turn, can rotate the outputelement 22 by way of a gear 21. The stator 11 is free to turn relativeto the hub 15 and relative to the hub 12 because the clutches 19, 18 aredisengaged.

The just outlined mode of operation is established when the outputelement 22 is to rotate in order to cause the transmission in the case 7to drive the motor vehicle in a forward direction at a speed which isestablished by the selected ratio of the transmission. The stator 11 isfree to turn in the fluid stream which is established in the housing 2by the rotating pump 3 and causes the turbine 8 to rotate the hub 12(and hence the output element 22) via connector 10, engaged clutch 13and gear 21. The rotating stator 11 does not transmit torque because theclutches 18 and 19 are disengaged. The RPM ratio ν is greater than theRPM ratio ν_(kupp) at the clutch point. The RPM ratio ν_(kupp) is therelationship between the turbine RPM ν_(turb) and the pump RPM ν_(pump).

The portion 25 of the internal space of the housing 2 can accomodate acustomary lockup clutch or bypass clutch (hereinafter called lockupclutch) which can be operated to establish a direct torque transmittingconnection between the output member of the prime mover (which drivesthe wall 2 a) and the output element 22. Such lockup clutch can beengaged to transmit torque by friction from the wall 2 a or from anotherpart of the housing 2 to an axially movable piston which can transmittorque to the output element 22, e.g., by way of the hub 12 and gear 21.A lockup clutch is shown (at 150) in FIG. 4.

The hub 15 for the stator 11 is normally held against rotation about theaxis I—I. An antifriction bearing 26 is provided between the rotary hub12 and the hub 15.

The clutches 13, 14, 18, 19 can be operated mechanically and/orhydraulically or in any other suitable manner. FIG. 1 shows anelectronic control unit 30 which has a plurality of signal receivinginputs 33 and signal transmitting connections with a first suitableactuator 31 for the clutches 14, 19 and a second suitable actuator 32for the clutches 13, 18. The actuators 31, 32 comprise or controlsuitable drive means such as electric motors and/or fluid-operatedmotors, magnets or the like. As used herein, the term “actuator” isintended to denote a “device that performs an action or outputs a signalin response to a signal from a computer” (see the Glossary of Terms in“Modern Automotive Technology” by James E. Duffy, published in 1994 bythe Goodheart-Wilcox Company, Inc.).

The signal processing and evaluating circuit of the control unit 30 canreceive signals from a number of various sensors and/or other monitoringmeans (e.g., circuits), such as RPM sensors, fuel consumption sensor(s),sensors which monitor the selected and/or the actual ratio of thetransmission, an electronic engine control circuit, an electroniccircuit which controls and monitors an antiskid device, one or moresensors denoting the presence or absence of an intent on the part of theoperator of the motor vehicle to shift the transmission in the case 7into a different gear, the condition of the brake(s) and/or others.

FIG. 2 shows a portion of the novel hydrokinetic torque converter 1 withits component parts in positions and conditions they assume when thetorque converter is called upon to increase the torque being transmittedfrom a prime mover (connected to the housing 2 and to the pump 3 in thehousing) to the rotary input element 22 of an automated transmission inthe case 7 (the input element 22 of the transmission also performs thefunction of the output element of the torque converter 1). The clutch 13is engaged so that the turbine 8 rotates the hub 12 which, by way of thegear 21, rotates the output element 22. The stator 11 is connected withthe hub 15 by way of the (engaged) clutch 19 so that the stator is heldagainst rotation because it is non-rotatably coupled to the transmissioncase 7 by the (engaged) gear 20. The torque converter 1 of FIG. 2increases the transmitted torque and drives its output element 22 (i.e.,the input element of the transmission in the case 7) in a forwarddirection. The torque converter is operated in the conversion mode,i.e., the stator 11 is held against rotation by the transmission case 7and the RPM ratio ν is less than the RPM ratio ν_(kupp) at the clutchpoint.

Referring to FIG. 3, the components of the hydrokinetic torque converter1 are shown in the positions and conditions they assume when the inputelement 22 is rotated in a direction to ensure that the transmission inthe case 7 drives the motor vehicle in reverse. The turbine 8 transmitstorque to the hub 15 by way of the connector 9 and (engaged) clutch 14.At the same time, the gear 20 connects the hub 15 with the stationarytransmission case 7 so that the hub 15 cannot rotate the input element22. The stator 11 is non-rotatably coupled to the hub 12 by way of the(engaged) clutch 18. The form-locking connection including the gear 21causes the input element 22 to rotate with the hub 12. The transmissionin the case 7 is shifted into reverse gear and the torque converter 1 isset to increase the torque; the turbine 8 is held against rotation andthe apparatus is in the conversion mode, i.e., the turbine 8 cannotrotate relative to the stationary (non-rotating) transmission case 7.The RPM ratio ν is less than the RPM ratio ν_(kupp) at the clutch point.

It will be seen that FIGS. 1, 2 and 3 show one and the same torqueconverter during three different stages (i.e., in three different modes)of operation. All that is necessary to shift from one of these modesinto a different mode is to move the hub 12 and/or 15 in the directionof the axis I—I. This causes selected clutches to become engaged ordisengaged and various form-locking connections (such as that includingthe gear 20) to become active or inoperative.

When the hubs 12, 15 are shifted axially of the input element 22 of thetransmission in the case 7 (i.e., of the output element of the torqueconverter 1) to the positions shown in FIG. 3, the turbine 8 is notconnected with the hub 12 (because the clutch 13 is disengaged), and thestator 11 is not connected with the hub 15 because the clutch 19 isdisengaged. The clutch 18 (e.g., a claw clutch) connects the stator 11with the output element 22 of the torque converter by way of the gear 21(e.g., a bevel gear).

In order to achieve a smooth transition from one gear into a differentgear of the transmission in the case 7, the torque converter 1 ispreferably provided, combined or associated with suitable synvhronizingmechanisms or units which are designed to conform the RPM of a drivingpart to the RPM of a driven part before such parts are positively (suchas form-lockingly) connected to each other by the respective ones ofvarious engageable and disengageable clutches. This will now bedescribed with reference to FIG. 4 which shows a portion of a secondhydrokinetic torque converter 101 having a housing 102 rotatable aboutan axis II—II. The housing 102 can constitute a deep drawn part made ofa metallic sheet material and includes two cupped sections 102 a, 102 bwhich are interfitted and their open ends are sealingly secured to eachother by a welded seam 102 c and/or in any other suitable way. Theradially inner portion 104 of the housing section 102 b is sealingly androtatably connected with the case 107 of a transmission by way of asuitable bearing 105 (e.g., an antifriction ball bearing) and at lastone sealing element 106.

The internal space of the housing 102 receives a pump 103 having vanesor blades which can be affixed to or made of one piece with the housingsection 102 a, a turbine 108 which is rotatable with and relative to thepump 103, and a stator 111 disposed between the radially inner portionsof the pump 103 and turbine 108.

The housing 102 further contains the aforementioned lockup clutch 150which is installed between the radially extending wall of the housingsection 102 a and the turbine 108. The radial wall of the housingsection 102 a is adjacent to and receives torque from the rotary outputmember of a prime mover, e.g., from the camshaft or crankshaft of aninternal combustion engine in the power train of a motor vehicle. Apower train is shown, for example, in FIG. 1 of the commonly owned U.S.Pat. No. 5,674,155 (granted Oct. 7, 1997 to Otto et al. for “METHOD OFAND APPARATUS FOR TRANSMITTING TORQUE IN THE POWER TRAINS OF MOTORVEHICLES”) which depicts schematically a power train including a primemover, an automated transmission, and a hydrokinetic torque converterwith lockup clutch between the prime mover and the transmission. Thedisclosure of this U.S. patent is incorporated herein by reference.

In normal operation, the prime mover drives the housing 102 which causesthe pump 103 to set the body of fluid in the housing in rotary motion,and such fluid imparts rotary motion to the turbine 108 and/or to thestator 111.

The turbine 108 comprises a shell 108 a having a radially inner portionwhich is affixed (e.g., riveted, as at 114) to a separately producedradially inner part 113. The part 113 of the turbine 108 comprises twoportions 113 a, 113 b at the opposite sides of the radially innerportion of the shell 108 a, and the portions 113 a, 113 b rotatablysurround an external collar 112 a of a rotary output element 112 of thetorque converter 101. A hub 120 for the turbine 108 is movable (towardand away from the collar 112 a) axially of the output element 112 butcannot rotate relative to such output element.

The peripheral surface of the collar 112 a is smooth and can be engagedby the internal surfaces of the aforementioned portions 113 a, 113 b ofthe radially inner part 113 of the turbine 108. Thus, when the hub 120is maintained in the axial position which is shown in FIG. 4, theturbine 108 and the output element 112 can rotate relative to eachother.

The output element 112 has an internal gear 112 b with teeth which meshwith the teeth of a complementary external gear 115 a provided on arotary input shaft 115 of the transmission in the case 107. The parts112, 115 can be said to constitute a composite output element of thetorque converter 101 or a composite input element of the transmission inthe case 107.

The radially innermost portion 102 d of the housing section 102 a is arelatively short cylinder or tube which serves as a means for centeringthe housing 102 on the output member of the prime mover.

FIG. 4 shows the torque converter 101 in a neutral condition. The stator111 and the turbine 108 can turn relative to the output element 112and/or vice versa, i.e., the input element 115 of the transmission inthe case 107 is not driven.

The hub 120 for the turbine 108 cannot turn relative to but can moveaxially of the output element 112. This is ensured by the provision of anon-referenced toothed connector including axially parallel externalteeth of the output element 112 and axially parallel internal teeth ofthe hub 120. When moved in a direction to the right, as viewed in FIG.4, the hub 120 can establish a torque transmitting connection betweenthe turbine 108 and the output element 112 by way of the part 113, andsuch connection is terminated (interrupted) in response to a movement ofthe hub 120 in a direction to the left, i.e., back to the axial positionof FIG. 4.

The turbine 108 comprises or cooperates with a second separatelyproduced inner part 130 having internal teeth movable into and out ofmesh with complementary external teeth of the hub 140 for the stator111. In the embodiment of FIG. 4, the second radially inner part 130 iscoupled with the turbine 108 by a conical connector 131 which is affixed(such as riveted at 132) to the radially inner part 130. The conicalconnector 131 has ports 131 a which permit the fluid (such as oil) toflow within the torus of the torque converter 101. It is preferred toinstall the conical connector 131 in that portion of the internal spaceof the housing 102 which receives the circulating portion of theconfined fluid. In lieu of utilizing a conical connector 131, it is alsopossible to employ two or more braces (not shown) or analogous partswhich define passages for the flow of fluid between them (i.e., suchpassages can replace the ports 131 a).

The hub 140 for the stator 111 is axially movably but non-rotatablycoupled to the transmission case 107. This hub is movable to and from anaxial position in which its external gear mates with a complementaryinternal gear of the part 130 to hold the turbine 108 against rotationwith the housing 102 and pump 103, i.e., to non-rotatably connect theturbine with the transmission case 107.

The stator 111 comprises a separately produced radially inner part 160having an internal gear adapted to mesh with a gear at the exterior ofthe hub 120 for the turbine 108. When such connection is established (inresponse to axial movement of the hub 120 in a direction to the left, asviewed in FIG. 4), the stator 111 is non-rotatably coupled to the outputelement 112 by way of the hub 120. Such connection between the outputelement 112 and the stator 111 can be terminated (interrupted) bydisengaging the internal gear of the radially inner part 160 from theexternal gear of the hub 120.

Furthermore, the internal gear of the radially inner part 160 of thestator 111 can be caused to mesh with a complementary external gear ofthe hub 140 to thus ensure that the stator 111 is non-rotatably attachedto the transmission case 107. Such connection between the stator 111 andthe transmission case 107 can be terminated (interrupted) in response toappropriate axial displacement of one of the internal gear of the part160 and the complementary external gear of the hub 140.

A thrust bearing 170 is provided between and rotatably couples thecoaxial hubs 120, 140 to each other for joint movement in the axialdirection of the torque converter 101. As already explainedhereinbefore, the hub 140 cannot but the hub 120 can rotate relative tothe stationary transmission case 107.

The hub 140 constitutes or acts as a piston or plunger which is receivedin a cylinder defined by or connected to the transmission case 107. FIG.4 shows that the cylinder for the piston or hub 140 is provided withsuitably distributed ports for the admission and evacuation of a fluidmedium which causes the hub 140 to move with the hub 120 to any one of aplurality of diferent axial positions. Depending upon the selected axialpositions of the hubs 120 and 140, the stator 111 and/or the turbine 108can be connected with or disconnected from the hub 120 or 140.

FIG. 4a shows a portion of the torque converter 101 of FIG. 4 drawn to alarger scale. The radially inner portion of the shell 108 a of theturbine 108 is secured to the portions 113 a, 113 b of the radiallyinner part 113 by the aforementioned rivets 114. The radially innerregion of the portion 113 a surrounds and is rotatable with reference tothe collar 112 a of the output element 112. The radially inner region ofthe portion 113 b constitutes or includes an internal gear 113 c whichcan be caused to mesh with an external gear 121 of the hub 120. Suchengagement between the gears 113 c, 121 can be brought about by movingthe hub 120 axially in a direction to the right, as viewed in FIG. 4a.

In the axial position which is shown in FIG. 4a, the hub 120 for theturbine 108 is disengaged from the first radially inner part 113 as wellas from the radially inner part 160 of the stator 111. When movedaxially in a direction to the right, as viewed in FIG. 4a (i.e., towardthe prime mover for the housing 102), a conical external frictionsurface of a first syncronizing ring 125 (having internal teeth meshingwith external teeth of the hub 120) is caused to engage a complementaryconical internal friction surface of a second synchronizing ring 126.The external friction surface of the second synchronizing ring 126 thenengages an internal friction surface of a third synchronizing ring 127.The rings 126, 127 are carried by the portion 113 b of the part 113,i.e., by the shell 108 a of the turbine 108. Frictional engagementbetween the abutting surfaces of the synchronizing rings 125, 126 and127 ensures that the difference between the RPM of the part 113 of theturbine 108 and the RPM of the hub 120 is gradually and predictablyreduced to zero or close to zero. Therefore, the external gear 121 ofthe hub 120 comes into mesh with the internal gear 113 c of the portion113 b of the part 113 when the RPM of the turbine 108 closelyapproximates or matches the RPM of the hub 120. The gears 113 c, 121establish a form-locking connection between the turbine 108 and the hub120, and the gears 112 c, 122 continue to maintain the hub 120 inform-locking torque transmitting engageent with the output element 112.

If the hub 120 is shifted from the axial position of FIG. 4a but in adirection to the left, the RPM of the part 160 is caused to conform tothe RPM of the hub 120 by way of synchronizing rings 161, 162. Thesynchronizing ring 162 surrounds the hub 120 and comes into frictionalengagement with the synchronizing ring 161 which is surrounded by andcan rotate the stator 111 as well as the part 160 which latter ismounted to share the angular movements of the stator. Thus, an axialmovement of the hub 120 in a direction to the left (as viewed in FIG.4a) results in the establishment of a torque transmitting connectionbetween the hub 120 and the part 160. The external gear 121 of the hub120 for the turbine 108 can mate with the internal gear 165 of the part160 of the stator 111 only when the RPM of the part 160 at leastapproximates the RPM of the hub 120 (in response to the activation ofthe synchronizing unit including the rings 161, 162). The stator 111 isthen in form-locking engagement with the hub 120.

The thrust bearing 170 ensures that the hub 140 for the stator 111shares all axial movements of the hub 120 for the turbine 108. Moreaccurately stated, the movements of he hub 120 in a direction to theright (as viewed in FIG. 4a) are initiated by the hub 140 in response toadmission of a pressurized fluid into the cylinder chamber 200 of thetransmission case 107 by way of a port 201, and the movements of thehubs 120, 140 in a direction to the left (again as viewed in FIG. 4a)are initiated in response to admission of a pressurized fluid into thecylinder chamber 203 or 204. A port 202 can serve for the evacuation ofsome fluid from the cylinder (transmission case 107) for the hub(piston) 140 and the hub 120.

In view of the aforedescribed connection (thrust bearing 170) betweenthe hubs 120 and 140, the leftward axial movement of the hub 120 resultsin the establishment of a torque transmitting connection between the hub120 and the part 160 of the stator 111 because the external gear 121 ofthe hub 120 then meshes with the internal gear 165 of the part 160. Afirst stage of such leftward movement of the the hubs 120, 140 involvesthe activation of a further synchronizing unit including synchronizingrings 142, 143, 144 whose operation is or can be identical with oranalogous to that of the synchronizing unit including the aforedescribedrings 125, 126 and 127. The synchronizing ring 142 is then in frictionalengagement with the synchronizing ring 143 which, in turn, is infrictional engagement with the synchronizing ring 144. The result isthat the RPM of the turbine 108 is reduced to zero or at least close tozero, and the external gear 141 of the hub 140 can mesh with theinternal gear 135 of the part 130 of the turbine 108. The synchronizingrings 142, 144 cannot rotate or can turn at a very low speed, and theintermediate synchronizing ring 143 (which has preferably conicalinternal and external friction surfaces respectively engageable withconical surfaces of the rings 142, 144) is compelled to share theangular movements of the turbine 108. For example, the synchronizingring 143 can be maintained in a suitable form-locking engagement withthe turbine 108.

It has been found that the synchronizing units including the rings125-127 and 142-144 can achieve a highly satisfactory equalization ofRPMs (including zero RPM) due to frictional engagement of theintermediate rings 126 and 143 with the respective pairs of rings 125,127 and 142, 144. The synchronizing rings 125, 127 (and/or thesynchronizing rings 142, 144) can be form-lockingly connected with eachother.

If the hub 120 is moved in a direction to the right, as viewed in FIG.4a, such axial movement is necessarily shared by the hub 140 (by way ofthe thrust bearing 170). This causes the friction surfaces of additionalsynchronizing rings 163, 164 to engage each other in order tosynchronize the RPM of the radially inner part 160 of the stator 111with the RPM of the hub 140, i.e., the RPM of the part 160 is reduced tozero because the hub 140 is in engagement with the stationarytransmission case 107 (i.e., the hub 140 cannot rotate about the axisII—II). Such reduction of the RPM of the part 160 to zero (or at leastclose to zero) takes place before the external gear 141 of the hub 140comes into mesh with the internal gear 165 of the part 160.

The bearings 116, 190, 191 and 192 are thrust bearings. The baring 116is installed between the housing 102 and the output element 112 of thetorque converter 101. The bearing 190 is installed between thetransmission case 107 (radially inwardly of the radial bearing 105) andthe part 130 of the turbine 108; the bearing 191 operates between theportion 130 a of the part 130 and the stator 111; and the bearing 192operates between the stator 111 and the portion 113 b of the part 113 ofthe turbine 108. One or more of the bearings 116 and 190-192 canconstitute an antifriction bearing or antifriction bearings (withspherical or other suitable rolling elements between pairs of races).Alternatively, at least one of the bearings 116, 190-192 can constitutea friction bearing (see the bearing 116).

The hub 140 has an internal gear 145 which meshes with an external gear107 a of the stationary transmission case 107 to thus ensure that thehub 140 cannot rotate about the axis II—II.

The thrust bearing between the hubs 120, 140 includes an inner racewhich is secured to the hub 120 (against axial movement relative to thehub 120) by a split ring 171 and/or in any other suitable way, and asecond split ring 172 is provided to secure the outer race of thebearing 170 to the hub 140. Such mounting of the bearing 170 ensuresthat the hubs 120, 140 are compelled to share all axial movements, thatthe hub 120 can turn relative to the hub 140, and that the hub 140 canbe non-rotatably secured to the transmission case 107 (at 107 a, 145)regardless of whether or not the hub 120 rotates about the axis II—II.The hubs 120, 140 are provided with suitable internal grooves for therespective split rings 171, 172. The two races of the thrust bearing 170can confine one or more annuli of spherical or other suitable rollingelements.

The synchronizing ring 161 is secured in a predetermined axial positionrelative to the stator 111 by a split ring 195, and a further split ring196 is provided to maintain the synchronizing ring 163 in apredetermined axial position relative to the stator 111. Thesynchronizing ring 143 us non-rotatably mounted in the portion 130 a ofthe part 130, and the synchronizing ring 126 is mounted in the portion113 b of the part 113 of the turbine 108.

That portion of the transmission case 107 which defines or constitutes acylinder, and the piston including the hubs 120, 140 and the thrustbearing 170 between the hubs 120, 140 constitute a double-actingcylinder and piston assembly with cylinder chambers 200, 203 or 200,204. As a rule, the fluid is a hydraulic fluid (such as oil). Thecontrols (not specifically shown in FIGS. 4 and 4a) for the admission offluid into and for the evacuation of fluid from the cylinder chambers200, 203 or 200, 204 are designed to ensure that the turbine 108 and thestator 111 are properly coupled to or uncoupled from the respective hubs120, 140. This renders it possible to control the output element 112 ofthe torque converter 101 in a manner which is required to shift thetransmission in the case 107 into neutral, into reverse gear, or into aforward gear.

In accordance with a modification, the motor means for effecting axialmovements of the hubs 120, 140 and the controls for such motor means canbe designed to move the two hubs independently of each other, e.g., byresorting to two discrete cylinder and piston assemblies or othersuitable actuators. The piston of one of the plural assemblies is thehub 120, and the piston 140 of the other assembly constitutes orincludes the hub 140. The utilization of two discrete assemblies rendersit possible to dispense with the thrust bearing 170 as well as with themeans for securing such bearing to the hubs 120 and 140. Thismodification will be readily understood upon perusal of the descriptionof FIGS. 4 and 4a.

FIG. 5 shows a portion of a hydrokinetic torque converter whichconstitutes a further modification of the torque converter 101 of FIGS.4 and 4a. More specifically, FIG. 5 shows a different mode of connectingthe turbine 108 and its part 113 with the output element 112 by way ofthe axially movable hub 120. The connection can serve to transmit torqueand can include at least some of the pairs of internal and externalgears which were described with reference to FIGS. 4 and 4a. The inputelement 115 of the transmission in the case 107 can receive torque fromthe turbine 108 but not from the stator 111 because the latter is heldagainst rotation about the axis of the torque converter due to itsconnection with the stationary transmission case 107 by way of the part160 and the hub 140.

FIG. 5 shows the torque converter in a condition it assumes when theinput shaft 115 of the transmission is rotated in a direction to effecta forward movement of the motor vehicle having a power train includingthe structure of FIG. 5. The stator 111 is connected with thetransmission case 107 so that it cannot rotate, and the rotating turbine108 transmits torque to the output element 112 because it is free torotate with the hub 120 which, in turn, rotates the output element 112(which rotates with the input element 115).

A lockup clutch 250 in the space between the turbine 108 and theadjacent radially extending wall 102 a′ of the driving section 102 a ofthe housing 102 comprises a piston 251 provided with a friction lining252 arranged to frictionally engage the inner side of a portion 253 ofthe wall 102 a′ when the clutch 250 is at least partially engaged. Thepiston 251 then transmits torque from the wall 102 a′ (i.e., from therotary output member of a prime mover) to the output element 112 by wayof a torsional vibration damper including one or more tangentially orcircumferentially extending coil springs 256. A somewhat similar torqueconverter with a damper and a lockup clutch is disclosed in commonlyowned U.S. Pat. No. 5,501,309 granted Mar. 26, 1996 to Walth et al. for“HYDROKINETIC TORQUE CONVERTER WITH LOCKUP CLUTCH”. The disclosure ofthis patent is also incorporated herein by reference.

A tubular or cylindrical radially innermost portion 251 a of the piston251 extends axially of the torque converter in a direction away from thewall 102 a′ and surrounds a portion of the output element 112. At leastone sealing element 254 (such as an O-ring) is interposed between thecylindrical portion 251 a of the piston 251 and the periphery of theoutput element 112.

If desired, the mounting of the radially innermost portion 251 a on theoutput element 112 can be such that the piston 251 and the outputelement 112 can turn relative to each other. The lockup clutch can beoperated by changing the ratio of fluid pressures in the housing 102 atopposite sides of the piston 251, i.e., between a first plenum chamber(located between the wall 201 a′ and the piston 251) and a second plenumchamber (between the piston 251 and the shell of the turbine 108). Thelockup clutch 250 can be fully disengaged (the friction lining 252 isthen out of contact with the portion 253 of the wall 102 a′), partiallyengaged (the friction lining 252 contacts but slips relative to theportion 253) or fully engaged (the piston 251 rotates with the housingsection 102 a without any slip).

In the lockup clutch 250 of FIG. 5, the friction lining 252 and theadjacent portion 253 of the wall 102 a′ extend exactly or at leastsubstantially radially of the axis of the torque converter. However, itis often preferred to provide a lockup clutch wherein a frustoconicalportion of the piston can engage and become partially or fullydisengaged from a complementary frustoconical portion of a wall formingpart of the driven rotary housing of the torque converter. Reference maybe had, for example, to the aforementioned '155 patent to Otto et al.Furthermore, the friction lining 252 can be omitted, such frictionlining can be provided on the portion 253 of the wall 102 a′, or afriction lining can be provided on each of the piston 251 and theportion 253 of the wall 102 a′.

The damper including the coil spring(s) 256 is connected to the piston251 (radially inwardly of the friction lining 252) by a set of rivets260 (only one shown in FIG. 5) or in any other suitable way. This dampercomprises two profiled washer-like members 255 a, 255 b which areaffixed to the piston 251, and a radially extending washer-like member257 received in the space between the members 255 a, 255 b. The members255 a, 255 b, 257 have registering windows for the illustrated coilspring 256. The radially innermost portion of the member 257 is a shortcylinder or tube having an internal gear 258 mating with an externalgear 259 provided on or forming part of the radially inner part 113 ofthe turbine 108.

When the lockup clutch 250 is engaged (as a result of shifting thepiston 251 axially so that the friction lining 252 is in frictionalengagement with the portion 253 of the wall 102 a′), the piston 251transmits torque from the housing 102 to the part 113 which rotates theturbine 108 so that the latter can rotate the output element 112 andhence the input element 115 of the transmission in the case 107. Themanner in which the hubs 120, 140 can be moved axially and theconstruction of various synchronizing units in the torque converter ofFIG. 5 are or can be the same as or analogous to those already describedwith reference to FIGS. 1-3 and 4-4 a.

The illustrated elementary (single-stage) damper of FIG. 5 can bereplaced with a more sophisticated damper (e.g., a multistage damper)and/or can be utilized in conjunction with one or more additionaldampers. For example, the torque transmitting connection between thepiston 251 and the part 130 of the turbine 108 can comprise a (first)set of tangentially or circumferentially extending coil springs 256forming part of a first damper, and a (second) set of tangentially orcircumferentially extending coil springs (e.g., within the springs 256)forming part of at least one second or additional damper. The pluraldampers can be arranged to operate in parallel or in series.

FIG. 6 shows a portion of a further torque converter wherein theconstruction of the lockup clutch 250 (including the piston 251 and itsdamper) is or can be identical with those described in connection withFIG. 5. One difference between the torque converters of FIGS. 5 and 6resides in the nature of the connection between the turbine 108 and itspart 130 on the one hand, and the hub 140 for the stator 111 on theother hand. The hub 140 is assumed to be fixedly (non-rotatably) securedto the case 107 of the transmission, and the torque converter is assumedto embody at least some of the aforedescribed means for operativelyconnecting certain coaxial parts with each other by means of matinggears, clutches or the like (reference may be had to FIGS. 4 and 4a).

The stator 111 rotates the input shaft 115 of the transmission in thecase 107 because the part 160 of the stator transmits torque to the hub120 for the turbine 108 and the hub 120 drives the output element 112which, in turn, drives the input element of the transmission. The mannerin which the just outlined torque transmitting connection between thestator 111 and the input element 115 of the transmission in the case 107is or can be accomplished is or can be the same as already describedwith reference to FIGS. 1-3, 4-4 a and 5.

FIG. 6 shows a sealing element 401 which seals the chamber 406(corresponding to the chamber 200 shown in FIG. 4a). This sealingelement 401 can be installed in the transmission case 107 at a givenradial distance from the axis of the torque converter of FIG. 6,particularly midway between the radially innermost and the radiallyoutermost surfaces of the annular hub 140 for the stator 111 (this isactually shown in FIG. 6). However, such sealing element (or anadditional sealing element) can also be installed in the transmissioncase 107 adjacent the radially outer (peripheral) cylindrical surface ofthe hub 140 or at the internal surface (as at 410).

In order to shift the hubs 120, 140 axially and in a direction to theright (as viewed in FIG. 6), a suitable pressurized fluid is admittedinto the chamber 406 by way of an inlet 402 in the transmission case107. This entails the expulsion of a corresponding quantity of fluidfrom the other chamber 403 at the right-hand axial end of the hub 120(the chamber 403 corresponds to the chamber 204 shown in FIG. 4a). Ifthe hubs 120, 140 are shifted in a direction to the left (e.g., back tothe axial positions shown in FIG. 6), the chamber 403 receivespressurized fluid from a source and the chamber 406 discharges acorresponding quantity of fluid by way of the port 402 and/or in adifferent way.

FIG. 6 further shows compartments 404, 405 at opposite sides of thepiston 251 of the lockup clutch 250. The latter is engaged when thepressure in the compartment 404 is caused to rise and the compartment405 is free to discharge a quantity of fluid corresponding to that whichis being admitted into the compartment 404. It is assumed here that thefluid in the compartments 404, 405 is a (non-compressible) hydraulicfluid.

The source of pressurized fluid (e.g., one or more pumps and/oraccumulators) and the various valves, conduits, sumps and other parts ofthe system which controls the flow of fluid into and from the chambers406, 403 as well as into and from the compartments 404, 405 are notshown in FIG. 6 for the sake of clarity and also because such systemsare well known in the art. For example, a pressurized fluid (such asoil) can be supplied to the chaber 406 or 403 as well as to thecompartment 404 or 405 by way of one or more axially extending channelsin the rotary input element 115 of the transmission in the case 107.

FIG. 6 shows the parts of the torque converter in the positions and/orconditions they assume when the transmission in the case 107 is ready toeffect a movement of the motor vehicle in reverse. As already mentionedabove, the turbine 108 is non-rotatably connected to the transmissioncase 107, and the stator 111 transmits torque to the output element 112of the torque converter.

The character 400 denotes a radial friction (slide) bearing having asubstantially I-shaped or L-shaped cross-sectional outline and beinginstalled between the portion 113 a of the part 113 of the turbine 108and the collar 112 a of he output element 112. The purpose of thebearing 400 is to take up radial stresses between the collar 112 a onthe one hand, and the turbine 108 on the other hand; furthermore, thebearing 400 is preferably designed and installed to take up axialstresses which the turbine 108 tends to transmit to the output element112.

It is preferred to establish the necessary or desired connections forthe turbine 108 (such as with the hub 120 or with the hub 140) prior orat least in part prior to the establishment of the necessary or desiredconnections for the stator 111 (e.g., with the hub 140 or with the hub120). The advantages of such mode of operation will be appreciated uponperusal of the description of the structure shown in FIG. 7 whichdepicts certain relevant details of the torque converter of FIG. 6.

The external gear 121 of the hub 120 for the turbine 108 is shown in anaxial position in which it meshes with an internal gear of thesynchronizing ring 125; however, the external gear 141 of the hub 140for the stator 111 is not (yet) in mesh with the internal gear of thesynchronizing ring 164. If the hub 140 is moved axially further in adirection to the right (as viewed in FIG. 7), the synchronizing ring 125cooperates with the rings 126, 127 of the corresponding synchronizingunit which brakes the turbine 108 and reduces its rotational speedsufficiently before the gear 121 comes into mesh with the internal gear113 c of the radially inner part 113 of the turbine.

Once the hub 140 and its external gear 141 have covered the axialdistance 301 (during their movement with the hub 120 in a direction tothe right, as viewed in FIG. 2), the external gear 141 comes into meshwith the internal gear of the synchronizing ring 164 which cooperateswith the rings 142, 143 of the respective synchronizing unit to brakethe stator 111 or to reduce the RPM of the stator to a desired value. Itwill be seen that the turbine 108 is synchronized prior tosynchronization of the stator 111.

The situation is analogous when the hubs 120, 140 are caused to move ina direction to the left (as viewed in FIG. 7). At such time, thesynchronizing ring 142 cooperates with the rings 143, 144 to synchronizethe turbine 108 via gear 141 and/or hub 140. This takes place before thehubs 120, 140 cover the distance 302 (as seen in the axial direction ofthe torque converter and in a direction to the left, as seen in FIG. 7).When the movement through the distance 302 is completed, the externalgear 121 of the hub 120, or the hub 120, engages the internal gear ofthe synchronizing ring 162 whereby the ring 162 cooperates with the ring161 to synchronize the stator 111.

In order to ensure a sequence of operations as described above withreference to FIG. 7, the distances between the synchronizing ranges ofthe synchronizing rings referred to in the description of FIG. 7 is lessthan the axial distance between those portions of the hubs 120, 140which act upon the synchronizing rings. This causes that one of thesynchronizing rings (namely the ring 125 or 142) is actuated by theoncoming hub and that another synchronizing ring is actuated uponcompletion of axial movement through the distance 301 or 302.

If the hubs 120, 140 are movable independently of each other, thesequence of axial movements of the two hubs is determined in advance soas to ensure that a synchronization of the turbine 108 takes place aheadof synchronization of the stator 111. All that is necessary is toproperly program the actuators or the controls for the actuators whichinitiate and effect the axial movements of the independently movable orshiftable hubs 120 and 140.

The transmission in the case 7 or 107 can be a stepped gearing or acontinuously variable transmission (CVT). Continuously variabletransmissions are described and shown, for example, in commonly ownedU.S. Pat. No. 5,667,448 granted Sep. 16, 1997 to Friedmann for “POWERTRAIN”. The disclosure of this patent is incorporated herein byreference.

The various clutches which are shown in FIGS. 1-3 can constitute clawclutches or form-locking clutches or any other cluches capable oftemporarily connecting the turbine and/or the stator with the turbinehub and/or with the stator hub.

The illustrated synchronizing units can be replaced by or utilized inconjunction with other types of synchronizing units. The illustratedsynchronizing units exhibit the important advantage that their spacerequirements are surprisingly small which is highly important in torqueconverters or in conjunction with torque converters to be put to use inthe power trains of motor vehicles. The feature that the illustratedsynchronizing units can be confined in the housing of a torque converteris particularly desirable and advantageous.

It is of further advantage to design the clutches in such a way thatthey can be located radially inwardly of the torus of the torqueconverter, or radially inwardly of the pump, stator and/or turbine. Thetorus is established by the space which is required for the flow offluid in the interior of the housing of the torque converter.

An important advantage of the axially movable hubs (such as 120 and 140)is that their end faces can be acted upon by a suitable pressurizedfluid so that such hubs can perform the functions of pistons or plungersin fluid-operated cylinder and piston motors. The advantages of theprovision of a coupling (such as a thrust bearing) between the hubs forthe turbine and the stator were pointed out hereinbefore. The advantageof a coupling which constitutes or includes a thrust (axial) bearing isthat the hub for the turbine can rotate about its axis while the hub forthe stator is held against rotation (such as by the case of thetransmission which receives torque from the output element of the torqueconverter).

The hydrokinetic torque converters which are shown in FIGS. 1 to 7 arepreferably designed in such a way that the clutches which serve toconnect or disconnect the turbine and/or the stator with and from thehousing or the output element of the torque converter are installed inthe housing, most preferably within the torus including the pump, theturbine and the stator. This contributes significantly to thecompactness of the torque converter, especially as seen in the radialdirection of the housing. The ability of the hubs for the turbine andfor the stator to move axially of the housing also contributes to thecompactness and simplicity of the torque converter, especially if theone and/or the other hub serves as a piston or plunger of afluid-operated cylinder and piston assembly. This renders it possible toachieve substantial savings in space and a considerable reduction of thetotal number of parts because it is not necessary to utilize one or moreadditional pistons, seals and other parts to move the hub for theturbine and/or the hub for the stator in the axial direction of thehousing.

FIG. 8 shows one-half of a hydrokinetic torque converter 200 which isrotatable about an axis A—A. The rotary housing 200 a of the torqueconverter 200 transmits torque to a pump 201 when the wall 205 a of thehousing in receives torque from the rotary output member 205 (e.g., acamshaft or a crankshaft) of a prime mover (such as an internalcombustion engine in the power train of a motor vehicle). The housing200 a further contains a turbine 202 which can rotate with and relativeto the pump 201, and two stators 203, 204.

The stator 204 is put to use when the transmission is to drive the motorvehicle in a forward direction. At such time, the pump 201 establishes acirculating flow of fluid in the housing 200 a, and more specificallywithin the torus defined by the parts 201 to 204, and such fluid flowrotates the turbine 202. The stator 204 deflects the fluid flow in atangential direction. The other stator 203 is put to use when the motorvehicle is to be driven in reverse; this stator constitutes a fourthelement of the torus and is free to rotate with the fluid flow when themotor vehicle is to be driven in a forward direction; at such time, thestator 203 does not effect or cause any appreciable deflection of thefluid flow in a tangential direction. However, the stator 203 (i.e., anelement of the torus) can cause a deflection of the fluid flow in theaxial and radial direction of the housing 200 a.

When the torque converter 200 operates in a forward mode, the turbine202 is connected with the input shaft 219 of the transmission. Aconnector 206 transmits torque from the turbine 202 to the clutch disc218 of a friction clutch 216 operating between the torque converter 200and the rotary input shaft 219 of an automated transmission. This clutchfurther comprises an axially movable pressure plate 217 which urges theclutch disc 218 against a radially extending friction plate of the inputshaft 219. The latter is installed in the stationary case 208 of thetransmission, and this case 208 is connected with the stator 204. Thothis end, a connector 210 of the stator 204 is connected with a frictiondisc 212 which is urged against a friction surface of the case 208 by anaxially movable pressure plate 213. At such time, the clutch discs 211and 215 are free to rotate about the axis A-A.

When the transmission in the case 208 is to drive the motor vehicle inreverse, the pump 201 is connected with the output member 205 of theprime mover by way of the wall 205 a of the housing 200 a. Therefore,when the housing 200 a is driven by the output member 205 of the primemover, the pump 201 causes the establishment of a fluid flow in thetorus. The turbine 202 is connected with the clutch disc 211 by way of aconnector 209, and the pressure plate 213 urges the clutch disc 211against the stationary case 208 of the transmission so that the turbine202 cannot rotate about the axis A-A.

When the motor vehicle is to be driven in reverse, the two stators 203,204 are connected with the input shaft 219 of the transmission in thecase 208 by way of the connectors 207, 210 and clutch discs 214, 215which are respectively acted upon by pressure plates 220 and 217. Atsuch time, the clutch discs 212, 218 are free to rotate about the axisA-A.

FIG. 9 shows one-half of a further hydrokinetic torque converter whichincludes a rotary housing 301 connected to the output member of a primemover (e.g., a camshaft or a crankshaft of an internal combustionengine). The turbine 303 in the housing 301 is connectable with suchhousing by way of a lockup clutch including an axially movable pressureplate 307. The lockup clutch further comprises a piston 308 which canmove the pressure plate 307 against a counterpressure plate 301 aaffixed to or forming part of the housing 301. Thus, when the lockupclutch including the parts 307, 308, 301 a is engaged, the turbine 303is compelled to rotate with the housing 301 due to frictional engagementbetween the parts 301 a, 307 and 308.

A second clutch including a clutch disc 310 affixed to the pump 304 ofthe torque converter of FIG. 9, an axially movable plate or piston 311,and a counterpressure plate 310 a of the housing 301 serves to separablycouple the pump 304 to the housing 301 in response to axial movement ofthe piston 311 in a direction to the left (as viewed in FIG. 9).

A third clutch 315 including the aforementioned piston 308, a clutchdisc 315 a and a piston 309 is provided to non-rotatably connect thestator 305 to the housing 301. To this end, a hub 306 is non-rotatablybut axially movably mounted (by mating gears) on the output element 306of the torque converter, and a radially inner part or hub 314 of thestator 305 is also connected with the output element 306 (i.e., with theinput element of the transmission) by mating gears or the like.

The clutch including the members 307, 308 is disengaged when the torqueconverter operates in the forward mode.

The pump 304 is connected with the housing 301 by a freewheel 312 insuch a manner that the freewheel 312 can turn in the direction ofrotation of the output member of the prime mover which drives thehousing 301 but the freewheel 312 prevents the pump 304 from rotating inthe opposite direction. The fluid in the torus including the turbine303, the pump 304 and the stator 305 circulates clockwise under theaction of the turbine 303 to rotate the stator 305 in the direction ofrotation of the housing 301, i.e., in the direction of rotation of theoutput member of the prime mover. The freewheel 312 holds the pump 304against rotation in the opposite direction, i.e., counter to thedirection of rotation of the housing 301.

The stator 305 and its radially inner part 314 are compelled to rotatewith the output element 306. This takes place when the composite lockupclutch including the clutch 315 and the clutch composed on the parts307, 301 a, 308, 317 is disengaged.

As already mentioned above, the radially inner part 314 of the stator305 can be connected for rotation with the output element 306, and thepiston 308 can establish a torque transmitting connection between thehousing 301 and the output element 306.

When the torque converter of FIG. 9 is set up to drive the motor vehiclein reverse, the clutch including the parts 310, 310 a, 311 is engaged sothat the pump 304 is compelled to rotate with the housing 301. Thepiston 311 then biases the clutch disc 310 against the counterpressureplate 310 a of the housing 301. The clutches including the parts 307,307 a, 308 and 309, 315 a (clutch 315) and 308, 315 a, 309, 317 aredisengaged and a freewheel 313 connects the turbine 303 for rotationwith the housing 301. Thus, the turbine 303 can turn in one directionbut is held against rotation relative to the housing 301 in the oppositedirection. The fluid circulates in the torus under the action of thepump 303 and rotates the stator 305 which causes its radially inner part314 to rotate the output element 306 in a counterclockwise direction.

The distribution of the parts 303, 304 and 305 is such that the pump 304and the turbine 303 are mirror images of each other and the stator 305is disposed in the clearance between the radially inner portions of theparts 303, 304.

The clutches 301 a, 307, 308 and 310, 310 a, 311 a are installed in theradially outer portion of the housing 301. The parts 307, 310 of theseclutches resemble discs (annuli) and are non-rotatably affixed to theturbine 303 and the pump 304, respectively.

The character 302 denotes the stationary case of the transmission whichreceives torque from the output element 306.

FIG. 10 shows a torque converter which differs from the torque converterof FIG. 9 in that the pump 404 extends along an arc of at least close to180° opposite a turbine 403 and a stator 405. The turbine 403 extendsalong an arc of at least close to 90°, the same as the stator 405, andthe turbine 403 is located radially outwardly of and surrounds thestator 405. The parts 403-405 are installed in the housing 401 of thetorque converter, and such housing is assumed to be driven by the rotaryoutput member (such as a crankshaft or a camshaft) of a prime mover(such as an internal combustion engine in the power train of a motorvehicle).

A first friction clutch 415 is provided to connect (when necessary) thepump 404 with the housing 401 when the motor vehicle is to be driven ina forward direction. At such time, a piston 411 of the clutch 415 urgesan axially movable pressure plate of the pump 304 against acounterpressure plate which is affixed to the housing 401. The piston411 is caused to engage the clutch 415 in response to a rise of fluidpressure in a plenum chamber 430 in the housing 401.

A second friction clutch 450 and a third friction clutch 407 areinstalled in the housing 401 radially outwardly of the stator 405adjacent the turbine 403. The clutches 407, 450 (which respectivelyinclude axially movable pistons 409, 408) are disengaged when the clutch415 is engaged. The clutch 407 further includes a clutch disc connectedwith the stator 405 by a connector 410, and a counterpressure plateaffixed to or forming part of the housing 401. The clutch 450 comprisesthe aforementioned piston 408 which can bias a clutch disc 408 a againsta counterpressure plate (piston 409 non-rotatably but axially movablymounted on the output element 406). A freewheel 413 connects the stator405 with the stationary case 402 of the transmission. The turbine 403drives the output element 406 by way of a hub 414 which can move axiallyof but cannot rotate relative to the output element 406. The stator 405can rotate (in one direction) relative to the transmission case 402 byway of a freewheel 412.

The clutch 450 can be engaged when the RPM of the turbine 403 and/orhousing 401 rises to a predetermined value; this causes the outputelement 406 to rotate with the housing 401 with or without slip. Thepiston 409 of the clutches 407, 450 is axially movably but non-rotatablyconnected with the hub 414 against rotation with the output element 406,but the piston 409 can move axially of the output element 406.

In the reverse mode, the stator 405 is connected with the housing 401 bythe flange-like connector 410 and the clutch 407. Such condition can bearrived at by raising the fluid pressure in a plenum chamber between thehousing 401 and the piston 408; this causes the piston 408 to bear uponthe clutch disc of the clutch 407 and to thus engage the clutch 407. Theclutches 450 and 415 are disengaged and the piston 411 is connected withthe transmission case 402 by way of a freewheel. The part 404 isconnected with the transmission case 402 by the freewheel 412 so that itcan rotate relative to the case 402 in one direction but is held againstrotation in the opposite direction. The part 405 acts as a pump and iscompelled to rotate with the housing 401. The part 403 performs thefunction of a turbine and transmits torque to the output element 406 ofthe torque converter. The part 404 performs the function of a stator.

The torque converters of FIGS. 9 and 10 can employ claw clutches andsynchronizing units between the radially inner part 314 of the part 305and the output element 306 of FIG. 9, as well as between the hub 414 andthe output element 406 of FIG. 10. An advantage of such designs is thatno superfluous drag torque need be transmitted when the transmission inthe case 302 or 402 is in neutral gear.

Referring again to FIG. 10, the part 417 serves to non-rotatably butaxially movably connect the piston 408 to the housing 401, and the part416 serves to non-rotatably but axially movably connect the piston 409to the hub 414.

FIGS. 11a, 11 b and 11 c show three different conditions of a furtherhydrokinetic torque converter. This torque converter comprises a housing501 a for four rotary components 501, 502, 503 and 504. At least one ofthese components can act as a pump, at least one other component can actas a turbine, and at least one further component can act as a stator.Three of these four components can be active when the torque converteris utilized to drive the wheels of a motor vehicle in a forwarddirection. One of the four components is then free to rotate. Three ofthe four components, but in a different combination, can be put to usewhen the torque converter is called upon to drive the motor vehicle inreverse; however, the geometry and the conversion characteristics aredifferent when the motor vehicle is driven while the associatedtransmission is shifted into reverse gear. Two stators can be rigidlyconnected to each other when the transmission is shifted into reversegear.

FIG. 11a shows the torque converter in a condition in which its outputelement 513 (this output element can constitute or it can be connectedwith the input shaft of a transmission in the case 514) is capable ofrotating in a direction to move the motor vehicle rearwardly. Thecomponent 501 acts as a pump and is driven by the housing 501 a which,in turn, is driven by the rotary output member 505 of the prime mover(e.g., the crankshaft or camshaft of an internal combustion engine).When the component (pump) 501 rotates, it effects a rotation of thecomponent (turbine) 502 and of one (504) of the components (stators)503, 504 whereby the component 504 effects a change of the direction offluid flow. within the torus. The part 503 (second stator) is effectivewhen the motor vehicle is driven in reverse; this component 503constitutes the fourth component of the torus and is free to rotate whenthe torque converter is caused to assume the condition or mode which isshown in FIG. 11a. At such time, the component 503 permits a change inthe direction of fluid flow as seen radially and axially of the housing501 a but does not permit a deflection in a tangential direction.

The component (turbine) 502 of the torque converter is non-rotatablyconnected with the output element 513 which latter comprises an externalgear mating with the internal gear of a hub 511 for the component(turbine) 502. The hub 511 and the connector 506 between the component502 and the hub 511 are provided with a synchronizing unit, e.g., amultiple-cone synchronizer, which serves to conform the RPM of the hub511 to that of the component 502, i.e., which at least reduces thedifference between the RPM of the component 502 and the RPM of the hub511 before the parts 502, 511 are form-lockingly connected to eachother.

The part (stator) 504 is mounted on its shaft by a freewheel 509 havingan internal gear adapted to mesh with an external gear on the hub 512for the component 504 upon appropriate synchronization of rotationalspeeds of the part 504 and the hub 512. The hub 512 is further providedwith an internal gear mating with an external gear on a coaxial shaftaffixed to or forming part of the transmission case 514. An antifrictionthrust bearing 520 is provided between the hubs 511 and 512.

The hubs 511 and 512 are movable axially of the torque converter by anactuator (e.g., a fluid-operated motor, an electric motor or the like).The torque converter is set for operation in a forward mode in responseto a leftward movement of the hubs 511, 512, namely toward the outputmember 505 of the prime mover.

In FIG. 11a, the hubs 511, 512 are located adjacent the transmissioncase 514. At such time, the transmission is ready to drive the motorvehicle in reverse. The component (pump) 501 is non-rotatably connectedwith the output member 505. If the prime mover is on, the rotatingcomponent (pump) 501 injects fluid into the component (turbine) 502which, in turn, deflects the fluid toward the component (stator) 503(this component is operative to effect a reverse movement of the motorvehicle) as well as toward the component (stator) 504. The connector 510for the component (turbine) 502 is non-rotatably coupled to thetransmission case 514. The components (stators) 503, 504 arenon-rotatably coupled to each other and operate to direct the fluid backinto the range of the component (pump) 501. Thus, in accordance with thejust outlined feature of the invention, the composite stator includingthe components 503, 504 turns in a direction counter to that of theoutput member 505 of the prime mover; therefore, the motor vehicle canbe driven in reverse.

At such time, the component (turbine) 502 is non-rotatably connectedwith the transmission case 514 (i.e., with the aforementioned shaftwhich is rigid with the transmission case and is caxial with the torqueconverter). The connector 510 has an internal gear meshing with anexternal gear on the hub 512, and an internal gear of the hub 512 is inmesh with an external gear of the output member 513. The engagementbetween the internal gear of the connector 510 and the external gear ofthe hub 512 takes place by way of a suitable synchronizing unit (notspecifically shown) which conforms the RPM of the component (turbine)502 to that of the hub 512 before the parts 510, 512 are non-rotatablycoupled to each other.

The components (stators) 503, 504 have internal gears which mate or areadapted to mate with external gears on the member 513. The internal gearof the radially inner part 507 of the component (stator) 503 and theinternal gear of the radially inner part 508 of the component (stator)504 are in mesh with one or more external gears of the hub 511. Thelatter has an internal gear which meshes with an external gear of theoutput element 513 (i.e., of the input element of the transmission inthe case 514). The hubs 511, 512 can move as a unit in the axialdirection of the torque converter between one end position (forwardmode, see FIG. 11b), another end position (reverse mode, see FIG. 11a),and an intermediate position (neutral mode, see FIG. 11c).

Referring to FIG. 11c, the hubs 511, 512 are not connected with thecomponents (composite stator means) 503, 504 and the component (turbine)502, respectively. The component (turbine) 502 and the components(stators) 503, 504 are free to rotate in the circulating fluid flowbecause they are not connected with the housing 501 a and/or with theoutput element 513 of the torque converter.

FIG. 12 shows one-half of a hydrokinetic torque converter including ahousing 605 containing a pump 601, a turbine 602, and stators 603, 604.The pump 601 is connected to and rotates with the housing 605 whichlatter can be driven by the rotary output member of a prime mover, notshown, e.g., by the camshaft or crankshaft of an internal combustionengine. The pump 601 can establish a fluid flow within the torus, andsuch fluid flow rotates the turbine 602. The stator 604 effects a changein the direction of the fluid flow. When the torque converter of FIG. 12operates in the forward mode, the stator 603 is free to rotate about thecommon axis of the parts 601, 602, 604.

In the forward mode, the turbine 602 is connected (by a connector 606)with the clutch disc 615 of a first friction clutch which furthercomprises an axially movable pressure plate 614 arranged to establish africtional engagement between the clutch disc 615 and the output shaft617 of the torque converter when the clutch including the parts 614, 615is engaged. At such time, a second friction clutch including the parts612, 613 is disengaged. The stator 604 is connected with the case 608 ofthe transmission in that the pressure plate 613 of the second clutchmaintains the clutch disc 612 (which is connected with the radiallyinner part 609 of the stator 604) in frictional engagement with thetransmission case 608. Two additional friction clutches 611, 616 aredisengaged so that the stator 603 is free to turn about the axis of thetorque converter.

When the torque converter of FIG. 12 is set to operate in the reversemode, the turbine 602 acts as a stator and the stator 603 drives theinput shaft 617 of the transmission. At such time, the connector 610 ofthe turbine 602 is non-rotatably secured to the transmission case 608 bythe pressure plate 613 and a clutch disc of the friction clutch 611. Atthe same time, the stator 603 is non-rotatably connected with the inputshaft 617 of the transmission by way of the hub 607 and the clutch 616including the pressure plate 614 and a clutch disc which bears againstthe hub 607. The clutches including the parts 614, 615 and 612, 613 aredisengaged. FIG. 12 shows that each of the two axially movable pressureplates 613 and 614 is common to two neighboring friction clutches.

When the torque converter of FIG. 12 is set to operate in the neutralmode, all four clutches are disengaged, i.e., the torque which can betransmitted between the pump 601 and the input element 617 of thetransmission is zero or close to zero.

FIG. 13 shows a further embodiment of a hydrokinetic torque converterwhich comprises a pump 701 connected to a rotary housing 705 adapted tobe driven by the output member of a prime mover. When the prime moverrotates the housing 705, the pump 701 establishes a flow of circulatingfluid within the torus in the interior of the housing 705. Thecirculating fluid rotates the turbine 702 so that an internal gear of aconnector 706 for the turbine can rotate the input element 712 of thetransmission by way of an axially shiftable hub 710 having an externalgear movable into and out of mesh with the internal gear of theconnector 706. The hub 710 further comprises an internal gear whichmates with an external gear of the input element 712.

When the torque converter of FIG. 13 is set to operate in the forwardmode, a stator 704 in the housing 705 is form-lockingly connected with ahub 711 which has an external gear then mating with an internal gear ofa radially inner part 708 of the stator 704. At such time, an internalgear of the hub 711 mates with an external gear of a shaft 713. Afreewheel then connects the stator 704 with the transmission case.

When the torque converter of FIG. 13 is set to operate in a reversemode, the hubs 710, 711 (which are rotatably coupled to each other by anantifriction thrust bearing 720) are held in such axial positions thatthe radially inner part 707 of the stator 703 is connected for rotationwith the hub 710 (by way of mating internal and external teth), i.e.,with the input element of the transmission. At the same time, theturbine 702 is connected with the shaft 713 for the stator 704 by way ofa connector 709 having an internal gear then meshing with an externalgear of the hub 711. The stator 704 is then free to rotate, the turbine702 acts as a stator, and the stator 703 drives the input element 712 ofthe transmission by way of the radially inner part 707.

An important advantage of the improved torque converter is that itcomprises a relatively small number of relatively simple parts; thiscontributes to compactness, simplicity and lower cost of the torqueconverter. Furthermore, and particularly if the torque converter isconstructed in a manner as shown, for example, in FIGS. 11a to 11 c, itcan operate with considerable savings in fuel when the parts of thetorque converter assume the position and conditions shown in FIG. 11c,i.e., when the input shaft of the transmission is disconnected from theturbine as well as from the stator(s) of the torque converter. Savingsin fuel entail a reduction of the quantity of emitted combustionproducts which, too, is an important feature of a motor vehicle having apower train which embodies the improved torque converter.

The aforedescribed pairs of mating gears can include spur gears orsplined shafts in combination with complementary internal gers, bevelgears and/or other types of gears.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic and specific aspects of our contributionto the art of hydrokinetic torque converters and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equvalence of the appended claims.

What is claimed is:
 1. A hydrokinetic torque converter comprising arotary housing; a pump confined in and rotatable by said housing; arotary turbine component and at least one rotary stator component insaid housing; a drive for said housing; an output device rotatable inclockwise and counterclockwise directions; means for connecting saidoutput device with one of said components to rotate the output device inone of said directions; and means for connecting said output device withthe other of said components to rotate said output device in the otherof said directions, wherein at least one of said connecting meanscomprises at least one friction clutch.
 2. The torque converter of claim1, wherein at least one other of said connecting means comprises atleast one engageable and disengageable clutch which permits therespective component to rotate said output device in the disengagedcondition of the clutch.
 3. The torque converter of claim 1, wherein atleast one other of said connecting means comprises at least oneform-locking clutch.
 4. The torque converter of claim 1, having a firstoperating mode in which said output device is connected with saidturbine to rotate in said one direction, and a second operating mode inwhich said output device is connected with at least one stator to rotatein said other direction.
 5. The torque converter of claim 4, wherein thetorque converter has a third operating mode in which said output deviceis disconnected from said turbine and from said at least one stator. 6.The torque converter of claim 4, further comprising at least oneengageable and disengageable clutch arranged to transmit torque betweensaid turbine and said output device in said first operating mode of thetorque converter.
 7. The torque converter of claim 6, further comprisinga rotary hub arranged to receive torque from said at least one clutchand form-locking connection arranged to transmit torque between said huband said output device.
 8. The torque converter of claim 4, furthercomprising at least one engageable and disengageable clutch arranged totransmit torque between said at least one stator and said output devicein said second operating mode of said torque converter.
 9. The torqueconverter of claim 8, further comprising a rotary hub arranged toreceive torque from said at least one clutch and form-locking connectionarranged to transmit torque between said hub and said output device. 10.The torque converter of claim 4, wherein at least one other of saidconnecting means comprises gears movable into and out of mesh with eachother.